PwPepwise

ARA-290 / Cibinetide

Healing & Recovery

EPO-derived 11-mer peptide

ARA-290, also known as cibinetide, is a small synthetic peptide derived from erythropoietin (EPO) — the hormone.

§Dosing at a glance

4 protocols · from the research
What it's forDoseHow oftenHowFor how long
Sarcoidosis-Associated Small Fiber Neuropathy (most established protocol)4 mg/dayWeeklySubcutaneousInjected just under the skin, into the fat layer.28 days
Type 2 Diabetes / Metabolic Neuropathy4 mg/day—SubcutaneousInjected just under the skin, into the fat layer.28 days
Diabetic Macular Oedema (investigational)4 mgDailySubcutaneousInjected just under the skin, into the fat layer.12 wks
Preclinical Reference Doses (animal models — not directly translatable to humans)3–60 µg/kgDailyIntraperitonealInjected into the abdominal cavity (research use).28 days

Approximate values pulled from the research — double-check before dosing.

§01Summary

ARA-290, also known as cibinetide, is a small synthetic peptide derived from erythropoietin (EPO) — the hormone that regulates red blood cell production — but engineered specifically to avoid stimulating red blood cell growth. Instead, it targets a distinct receptor complex in tissues throughout the body that promotes cell survival, reduces inflammation, and supports nerve repair. This receptor, sometimes called the innate repair receptor, is found on nerve cells, immune cells, pancreatic cells, heart muscle, and other tissues.

In clinical studies focused on sarcoidosis-associated small fiber neuropathy — a painful nerve condition — ARA-290 at 4 mg/day increases corneal nerve fiber density1,2 and improves neuropathic symptom scores3, suggesting both symptomatic and potentially disease-modifying effects. It may also improve metabolic markers including HbA1c and lipid profiles in people with type 2 diabetes6. Preclinical research points toward a broad range of potential applications including wound healing17, islet transplantation support15,18, cardiovascular aging13, and bone preservation19. Because it does not stimulate erythropoiesis, ARA-290 avoids the blood-thickening and clotting risks associated with standard EPO therapy8,10, making it a promising platform for tissue-protective indications that are actively under clinical investigation.

This is the layperson summary. Mechanism, dosing, the evidence base, and the published literature are in the sections below — every claim links to its source.

§02In depth

ARA-290 (cibinetide) is an 11-amino acid cyclic peptide derived from the three-dimensional surface topology of erythropoietin, specifically engineered to selectively engage the heteromeric innate repair receptor (IRR) — a complex composed of the erythropoietin receptor (EPOR) and the β-common receptor (CD131/βcR) — while avoiding activation of the homodimeric EPOR responsible for erythropoiesis8,10. This receptor selectivity is the molecular basis for its tissue-protective effects without hematopoietic activity. The IRR is expressed broadly across non-hematopoietic tissues including peripheral neurons, macrophages, dendritic cells, Schwann cells, cardiomyocytes, pancreatic islet cells, endothelial cells, and skeletal muscle10,15,20.

Upon IRR engagement, ARA-290 activates intracellular signaling cascades including the JAK2/STAT and PI3K/Akt/eNOS pathways. In macrophages and myeloid cells, IRR activation — specifically requiring both CD131 and JAK2 functionality — inhibits NF-κB subunit p65 activity, suppressing transcription of pro-inflammatory mediators including TNF-α, IL-1β, IL-6, and MCP-116,15. In peripheral nerve tissue, the peptide appears to suppress spinal cord microglial reactivity (iba-1-IR) in a dose-dependent manner without affecting astrocyte activation (GFAP-IR), suggesting selective modulation of microglia-mediated neuroinflammation over astrogliosis9. The molecular pathway through which β-common receptor signaling mediates neuropathic pain relief appears to be shared with at least one other clinically relevant compound: knockout studies in βcR-null mice demonstrate that ketamine loses its neuropathic — but not acute — analgesic efficacy in the absence of an intact IRR, with convergent downstream modulation of NMDAR expression, microglial markers, and CCL211.

In peripheral nerve repair contexts, ARA-290 promotes Schwann cell proliferation and inhibits their inflammatory activation in vitro, while in vivo shifting T-helper cell balance toward regulatory Foxp3+ and Th2 phenotypes and away from Th1 responses, and enhancing the phagocytic clearance function of macrophages10. In vascular and wound healing contexts, IRR activation upregulates VEGF, phospho-Akt, and phospho-eNOS while reducing oxidative stress (malondialdehyde), supporting angiogenesis and re-epithelialization17. In bone metabolism, ARA-290 inhibits osteoclastogenesis through the EPOR/CD131 heteromeric complex and increases cortical (~5.8%) and trabecular (~5.2%) bone mineral density in female mice, distinguishing the tissue-protective heteromeric receptor from the homodimeric EPOR, which appears to promote bone resorption19.

In the cardiovascular aging context, chronic ARA-290 treatment reduces age-related cardiac leukocyte and monocyte infiltration, attenuates NF-κB signaling and pro-inflammatory cytokine accumulation, enhances cardiomyocyte autophagy flux, reduces lipofuscin accumulation, and desensitizes mitochondrial permeability transition pore opening in response to oxidative stress — a constellation of effects consistent with broad mitochondrial and proteostatic cytoprotection beyond anti-inflammation alone13. In early Alzheimer's-like pathology, ARA-290 expands the Ly6C-Low patrolling monocyte subset from bone marrow progenitors, a population implicated in cerebrovascular amyloid clearance, suggesting an upstream hematopoietic progenitor modulation pathway distinct from its direct tissue-protective signaling12.

§04Evidence & efficacy

Evidence base
109Studies
40Human
12Animal

ARA-290/cibinetide has demonstrated the most consistent and replicated efficacy evidence in sarcoidosis-associated small fiber neuropathy. Three independent RCTs in this indication collectively show that treatment increases corneal nerve fiber density2,3, improves neuropathic symptom scores on validated instruments (SFNSL)3, and at 4 mg/day significantly increases corneal nerve fiber area compared to placebo (placebo-corrected mean change +697 µm², P=0.012)1. Changes in corneal nerve fiber area correlated with both intraepidermal nerve fiber regeneration (ρ=0.575, P=0.025) and functional capacity as measured by the 6-minute walk test (ρ=0.645, P=0.009)1, and increases in regenerating GAP-43+ intraepidermal fibers were also statistically significant (P=0.035)1. Neuropathic symptom questionnaire scores showed significant between-group improvement versus placebo in the earliest pilot trial (SFNSL Δ–11.5 vs Δ–2.9, p<0.05)3. Quality of life and physical functioning domains of the SF-36 may improve with treatment3.

In type 2 diabetes, ARA-290 at 4 mg/day for 28 days appears to improve HbA1c, lipid profiles, and neuropathic symptom scores, with corneal nerve fiber density increases observed in subjects with notably reduced baseline fiber density, and effects persisting through a 28-day post-treatment observation window6.

In preclinical models, ARA-290 has demonstrated dose-dependent, long-lasting relief of mechanical and cold allodynia for up to 20 weeks following only 5 doses in a rat spared nerve injury model9, and has shown efficacy in experimental autoimmune neuritis, improving clinical recovery, nerve regeneration, and remyelination10. Preliminary animal evidence suggests potential benefits in islet transplantation engraftment15,18, diabetic wound healing17, age-related cardiac inflammation and function13, bone mineral density preservation19, and early-stage Alzheimer's-like amyloid pathology12. In a db/db mouse model of type 2 diabetes, ARA-290 improved peripheral insulin sensitivity and monocyte profiles but did not rescue executive cognitive flexibility deficits, highlighting the boundaries of peripheral immunometabolic targeting for central outcomes14.

§05Safety

Across completed human trials, ARA-290/cibinetide has demonstrated a consistently favorable tolerability profile. No significant adverse events were reported in the randomized controlled trials conducted in sarcoidosis patients2,3 or in the open-label type 2 diabetes study6. The drug was self-administered subcutaneously in outpatient settings without noted safety discontinuations, suggesting good local and systemic tolerability1,6. In the earliest pilot RCT, no safety concerns were raised by clinical or laboratory assessments including hematology, kidney function, and liver function monitoring3.

A key safety advantage of ARA-290 over native erythropoietin is its selective binding to the heteromeric innate repair receptor (EPOR/CD131) rather than the homodimeric EPO receptor responsible for erythropoiesis. Accordingly, ARA-290 does not stimulate red blood cell production and is not expected to carry the thrombotic, polycythemic, or cardiovascular risks associated with recombinant EPO8,10,19. This distinction has been consistently confirmed across both human and preclinical studies2,9,10,15.

In animal models, ARA-290 was well tolerated across multiple species, routes of administration, and dose levels, including chronic 15-month administration in aged rats13 and perioperative high-dose protocols in transplantation models18. No hematopoietic effects were observed in any animal study10,15,18,19.

Long-term human safety data beyond 28–56 days is an area of active investigation, and formal pharmacovigilance data from larger phase 3 populations are still emerging.

§06History

ARA-290 emerged from work by Nobel laureate Anthony Cerami and Michael Brines at The Kenneth S. Warren Institute and later Araim Pharmaceuticals, building on their foundational discovery that erythropoietin exerts tissue-protective effects through a receptor complex distinct from its erythropoietic receptor. Recognizing that full-length EPO carried significant cardiovascular and thrombotic risks when used for tissue protection, their team identified a surface helix of EPO responsible for binding the heteromeric EPOR/CD131 innate repair receptor and synthesized ARA-290 as an 11-amino acid cyclic peptide mimicking this structural motif without erythropoietic activity8.

The first published human evidence appeared in 2012–2013, when a randomized double-blind pilot study in sarcoidosis patients with small fiber neuropathy demonstrated significant improvements in neuropathic symptom scores and corneal nerve fiber density3. A larger confirmatory RCT followed shortly thereafter, reinforcing these structural and functional findings2. By 2015, an open-label study extended the clinical evidence to type 2 diabetes, showing metabolic and neuropathic benefits alongside corneal nerve fiber regeneration6. The 2017 phase 2b dose-ranging RCT — the highest-quality trial in this dataset — confirmed the 4 mg/day subcutaneous dose as optimal and established corneal confocal microscopy as a validated surrogate endpoint for small fiber neuropathy trials1. Araim Pharmaceuticals subsequently advanced development through multiple registered trials including sarcoidosis neuropathy, diabetic macular oedema, and metabolic disease5,7,4. Parallel preclinical research programs have expanded the evidence base into transplantation15,18, autoimmune neuropathy10, cardiovascular aging13, and neurodegeneration12, establishing ARA-290 as a broad-platform tissue-protective compound with an actively growing translational research landscape.

§07References